- 1-Bromo-2,6-dihydroxybenzene containing R44(8) rings and C(2) helices
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Molecules of the title compound (also known as 2-bromoresorcinol), C 6H5BrO2, are essentially planar and possess normal geometrical parameters. The crystal packing is influenced by O - H...O and O - H...O/Br hydrogen bonds
- Kirsop, Peter,Storey, John M. D.,Harrison, William T. A.
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Read Online
- Total Synthesis of Caesalpinnone A
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Total synthesis of caesalpinnone A was achieved in 12 steps starting from resorcinol. Key features of the synthesis include BINOL-phosphoric acid catalyzed [4 + 2] cycloaddition, trans-selective nucleophilic substitution, deallylation/oxa-Michael addition cascade, and late-stage photo-Fries rearrangement.
- Liu, Zhigang,Meng, Yifei,Yuan, Pengrui,Wang, Zhengshen,Gao, Jin-Ming,Zheng, Huaiji
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supporting information
p. 520 - 522
(2020/01/21)
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- Kolbe-Schmitt type reaction under ambient conditions mediated by an organic base
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The combined use of an organic base for resorcinols realized a Kolbe-Schmitt type reaction under ambient conditions. When resorcinols (3-hydroxyphenol derivatives) were treated with DBU under a carbon dioxide atmosphere, nucleophilic addition to carbon dioxide proceeded to afford the corresponding salicylic acid derivatives in high yields.
- Sadamitsu, Yuta,Okumura, Akira,Saito, Kodai,Yamada, Tohru
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supporting information
p. 9837 - 9840
(2019/08/20)
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- Synthesis of tetra-pincer nickel(ii) and palladium(ii) complexes of resorcin[4]arene-octophosphinite [Res(OPR2)8] and rhodium-catalyzed regioselective hydroformylation reaction
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The condensation reaction of resorcinol with pentanal yielded resorcin[4]arene 1 which on bromination using N-bromosuccinimide at room temperature produced tetra-bromide derivative 2. The reactions of 2 with chlorodiphenylphosphine and o-phenylenephosphoro-chloridite yielded octaphosphinite 3 (hereafter referred to as octaphos) and octaphosphite 4, respectively. The reactions of 3 with Ni(COD)2 or Pd2(dba)3·CHCl3 in appropriate molar ratios yielded tetra-pincer complexes 5 and 6, respectively. The structures of both the complexes were established by single crystal X-ray diffraction studies. The resorcin[4]arene backbone adopts a boat structure in these complexes. Typically, the Rh-catalyzed hydroformylation of styrene prevalently delivers a branched (b) chiral aldehyde. A unique resorcin[4]arene skeleton based octaphos 3 was employed in the Rh-catalyzed hydroformylation of styrene. The hydroformylation of styrene with a metal to ligand ratio of 1:1 (M:L) was found to be regioselective, producing a linear (l) aldehyde as a major product with 100% conversion in 3 h. The l:b ratio surprisingly increased when the ortho positions of styrene were populated by methyl and chloro substituents. The hydroformylation of p-nitro styrene triggered a remarkably high linear:branched aldehyde ratio of 2.4 (71% linear aldehyde) despite its electron withdrawing nature. The highest linear selectivity of 97% (l:b ratio 27.8) was achieved in the case of 2,4,6-trimethylstyrene.
- Ananthnag, Guddekoppa S.,Mondal, Dipanjan,Mague, Joel T.,Balakrishna, Maravanji S.
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p. 14632 - 14641
(2019/10/16)
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- A dehydrobenzene precursor and its synthetic method
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The invention discloses a benzyne precursor and a synthesis method thereof. The benzyne precursor has a structure shown as the formula which is shown in the specification. The synthesis method of the benzyne precursor comprises the two steps: synthesizing
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Paragraph 0039; 0042
(2017/02/24)
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- Trifluoromethanesulfonyloxy-group-directed regioselective (3 + 2) cycloadditions of benzynes for the synthesis of functionalized benzo-fused heterocycles
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Highly regioselective (3 + 2) cycloadditions of (trifluoromethanesulfonyloxy)benzynes [(triflyloxy)benzynes] with 1,3-dipoles followed by cross-coupling reactions provided multisubstituted benzo-fused heterocycles. The triflyloxy group at the 3-position of benzynes, and even that at the remote 4-position, greatly affected the regiocontrol of the cycloaddition. These groups also served to install other substituents at their ipso-positions.
- Ikawa, Takashi,Kaneko, Hideki,Masuda, Shigeaki,Ishitsubo, Erika,Tokiwa, Hiroaki,Akai, Shuji
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supporting information
p. 520 - 526
(2015/02/05)
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- Synthesis of 13C4-labelled oxidized metabolites of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene
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Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BaP), are ubiquitous environmental contaminants that are implicated in causing lung cancer. BaP is a component of tobacco smoke that is transformed enzymatically to active forms that interact with DNA. We reported previously development of a sensitive stable isotope dilution LC/MS method for analysis of BaP metabolites. We now report efficient syntheses of 13C4-BaP and the complete set of its 13C4-labelled oxidized metabolites needed as internal standards They include the metabolites not involved in carcinogenesis (Group A) and the metabolites implicated in initiation of cancer (Group B). The synthetic approach is novel, entailing use of Pd-catalyzed Suzuki, Sonogashira, and Hartwig cross-coupling reactions combined with PtCl2-catalyzed cyclization of acetylenic compounds. This synthetic method requires fewer steps, employs milder conditions, and product isolation is simpler than conventional methods of PAH synthesis. The syntheses of 13C4-BaP and 13C4-BaP-8-ol each require only four steps, and the 13C-atoms are all introduced in a single step. 13C4-BaP-8-ol serves as the synthetic precursor of all the oxidized metabolites of 13C-BaP implicated in initiation of cancer. The isotopic purities of the synthetic 13C 4-BaP metabolites were estimated to be ≥99.9%.
- Wu, Anhui,Xu, Daiwang,Lu, Ding,Penning, Trevor M.,Blair, Ian A.,Harvey, Ronald G.
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body text
p. 7217 - 7233
(2012/09/05)
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- Urolithin as a Converging Scaffold Linking Ellagic acid and Coumarin Analogues: Design of Potent Protein Kinase CK2 Inhibitors
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Casein kinase2 (CK2) is a ubiquitous, essential, and highly pleiotropic protein kinase; its abnormally high constitutive activity is suspected to underlie its pathogenic potential in neoplasia and other relevant diseases. Previously, using different in silico screening approaches, two potent and selective CK2 inhibitors were identified by our group: ellagic acid, a naturally occurring tannic acid derivative (Ki=20nM) and 3,8-dibromo-7-hydroxy-4-methylchromen-2-one (DBC, Ki=60nM). Comparing the crystallographic binding modes of both ellagic acid and DBC, an X-ray structure-driven merging approach was taken to design novel CK2 inhibitors with improved target affinity. A urolithin moiety is proposed as a possible bridging scaffold between the two known CK2 inhibitors, ellagic acid and DBC. Optimization of urolithinA as the bridging moiety led to the identification of 4-bromo-3,8-dihydroxy-benzo[c]chromen-6-one as a novel, potent and selective CK2 inhibitor, which shows a Ki value of 7nM against the protein kinase, representing a significant improvement in affinity for the target compared with the two parent fragments. Two become one: Comparing the crystallographic binding modes of ellagic acid (red) and 3,8-dibromo-7-hydroxy-4-methylchromen-2-one (DBC; blue), an X-ray structure-driven merging approach to the design of novel casein kinase2 (CK2) inhibitors was taken. Using this strategy, a potent and selective urolithin derivative, 4-bromo-3,8-dihydroxy-benzo[c]chromen-6-one was identified, which exhibits a Ki value of 7nM against CK2.
- Cozza, Giorgio,Gianoncelli, Alessandra,Bonvini, Paolo,Zorzi, Elisa,Pasquale, Riccardo,Rosolen, Angelo,Pinna, Lorenzo A.,Meggio, Flavio,Zagotto, Giuseppe,Moro, Stefano
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experimental part
p. 2273 - 2286
(2012/04/11)
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- Enantioselective synthesis of (+)-estrone exploiting a hydrogen bond-promoted Diels?Alder reaction
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Starting from Danes diene and methylcyclopentenedione, (+)-estrone is synthesized along the Quinkert?Dane route in 24% total yield. The key step is an enantioselective Diels?Alder reaction promoted by an amidinium catalyst as efficiently as by a traditional Ti-TADDOLate Lewis acid.
- Weimar, Marko,Duerner, Gerd,Bats, Jan W.,Goebel, Michael W.
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supporting information; experimental part
p. 2718 - 2721
(2010/07/17)
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- Towards allosteric receptors - Synthesis of Resorcinarene-Functionalized 2,2′-Bipyridines and their metal complexes
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Based on a first: example of an allosteric hemicarcerand (1) we prepared four new 2,2′bipyridines that carry resorcinarene moieties in a highly convergent manner. Upon coordination to suitable transition metal ions or their complexes these compounds undergo conformational changes in a way that: they switch between "open" and. "closed" forms (2, 3, and 4) or vice versa (5), thus, bringing together or separating the two functional, moieties on the central, bipyridine, Among the transition metal complexes that act: as effectors for the conformational switching, [Re(CO)5Cl] and monomeric copper(I) complexes of sterically hindered 2,9-arylated 1,10-phenanthrolines proved, to be very effective.
- Staats, Holger,Eggers, Friederike,Hass, Oliver,Fahrenkrug, Frank,Matthey, Jens,Luening, Ulrich,Luetzen, Arne
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experimental part
p. 4777 - 4792
(2009/12/25)
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- A facile route to Aryl-substituted 1,10-phenanthrolines by means of Suzuki coupling reactions between substituted areneboronic acids and halogeno-1,10-phenanthrolines
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Twelve new mono- or diaryl-substituted 1,10-phenanthrolines (17 and 18) have been synthesized. The key step is a Suzuki coupling reaction between the substituted areneboronic acids 6, 11, and 15 and the mono- and dihalo-1,10-phenanthrolines 16. The syntheses of bis-ortho-substituted boronic acids 6, 11, and 15 from substituted arenes 5 or substituted bromoarenes 10 and 14 by lithiation and subsequent treatment with trimethyl borate is described. Not only 2,9-diiodo- (16c) but also 2,9-dichloro-1,10-phenanthroline (16b) can be used with good yields (65-92%) in the described Suzuki coupling. For the syntheses of unsymmetrically substituted 1,10-phenanthrolines 18b, 18i, and 18j, the use of 2- chloro-9-iodo-1,10-phenanthroline is not necessary; two different bis-ortho-substituted arene rings can be introduced stepwise in 46 to 64% total yield. ( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).
- Luening, Ulrich,Abbass, Michael,Fahrenkrug, Frank
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p. 3294 - 3303
(2007/10/03)
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- Catalytic Halogenation of Selected Organic Compounds Mimicking Vanadate-dependent Marine Metalloenzymes
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The ammonium metavanadate, mimicking vanadate-dependent metalloenzymes, efficiently catalyses the halogenation of a variety of organic substrates in dilute conditions in moderate to good yields using dilute hydrogen peroxide (30percent) as an oxidizing agent exhibiting remarkable ortho selectivity with electron-rich aromatics.
- Dinesh, Chimmanamada U.,Kumar, Rajiv,Pandey, Bipin,Kumar, Pradeep
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p. 611 - 612
(2007/10/02)
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- Bromophloroglucinols and their methyl ethers
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All 16 bromination products of phloroglucinol and its methyl ethers, as well as five bromoresorcinols and three of their dimethyl ethers, were synthesized and analyzed by nuclear magnetic resonance spectroscopy.Two or three equivalents of bromine convert phloroglucinol to di- and tribromophloroglucinol, 5-methoxyresorcinol to the tri- and 2,4-dibromo, 3,5-dimethoxyphenol to the tri- and 2,6-dibromo, and 1,3,5-trimethoxybenzene to the dibromo compound.With one equivalent of bromine, 3,5-dimethoxyphenol reacts preferentially at C-2 while 5-methoxyresorcinol gives both monobromo isomers.Partial debromination with sodium sulfite yields successively 2,4-dibromo- and 2-bromo-5-methoxyresorcinol from the tribromo compound but fails with brominated 3,5-dimethoxyphenol.In the resorcinol series, C-2 is invariably the least reactive position. 4,6-Dibromo-5-methoxyresorcinol and 2,4-dibromo-3,5-dimethoxyphenol are accessible by methylation of dibromophloroglucinol, obtained from 3,5-dibromo-2,4,6-trihydroxybenzoic acid by decarboxylation.In contrast to resorcinol and tribromoresorcinol, the partial bromination of pholoroglucinol and debromination of tribromopholoroglucinol are not selective.The 13Cnmr spectra of bromophloroglucinol methyl ethers show characteristic downfield shifts for methoxy groups orthogonal to the aromatic ring plane.
- Kiehlmann, E.,Lauener, R. W.
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p. 335 - 344
(2007/10/02)
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